Download Agents that kill or destroy bacteria are said to be The killing or

Agents that kill or destroy bacteria are said to be
A) inhibitory.
B) bacteriocidal.
C) bacteriostatic.
D) all of the above.
The killing or removal of all viable life forms is called
A) disinfection.
B) sterilization.
C) decontamination.
D) any of the above, depending on the circumstances.
The action of bacteriolytic chemical agents can be observed by noting a(n)
A) increase in the turbidity of the medium.
B) decrease in the turbidity of the medium.
C) change in the color of the medium.
D) change in the surface tension of the medium.
In the agar diffusion method of studying antimicrobial action, the __________ is measured.
A) diameter of the zone of inhibition
B) diameter of the individual microbial colonies
C) turbidity of the medium
D) distance between the microbial colonies
Sulfanilamide is an analog of
A) citric acid.
B) p-aminobenzoic acid.
C) folic acid.
D) sulfuric acid.
The quinolones are synthetic antibacterial compounds that
A) interact with bacterial DNA gyrase.
B) increase the supercoiling rate in the bacterial DNA.
C) prevent the formation of pre-RNA segments.
D) all of the above.
Semisynthetic antibiotics
A) are natural antibiotics that have been chemically modified in the laboratory.
B) have an artificially constructed core that stimulates the production of "natural products."
C) are found in nature but their rate of production is enhanced in the laboratory.
D) are natural antibiotics that have been purified by artificial means.
Disinfectants
A) Are chemicals that kill many different kinds of pathogens.
B) Are used inside the human body to kill bacteria.
C) Kill microbes by inducing mutations.
D) Remove water from bacteria.
Primary targets for antibiotic action include
A) the cell wall.
B) the cytoplasmic membrane.
C) DNA replication and transcription.
D) all of the above.
The β-lactam antibiotics
A) inhibit plasma membrane synthesis.
B) inhibit cell wall synthesis.
C) inhibit protein synthesis.
D) prevent chromosomal replication.
Erythromycin acts as a(n)
A) protein synthesis inhibitor at the level of the 50S subunit of the ribosome.
B) protein synthesis inhibitor at the level of the 30S subunit of the ribosome.
C) nucleic acid enzyme inhibitor.
D) inhibitor of ribosome production.
Many bacteria acquire antibiotic resistance by the transfer of __________ from a resistant
organism to a sensitive one.
A) Pili
B) Mutations
C) Plasmids
D) Endospores
Antimicrobial activity is measured by determining the smallest amount of agent needed to
inhibit the growth of a test organism, a value called the __________.
Pathogens are often encased and grow in large numbers as __________, covering the surfaces
of tissues with several layers of microbial cells.
Which statement(s) is/are true?
A) Microbial parasites are often called pathogens.
B) Virulence is a quantitative measure of pathogenicity.
C) The outcome of a host-parasite relationship varies considerably depending on the susceptibility of the host to
the parasite.
D) All of the above.
Which of the following is an endotoxin?
A) Cholera toxin
B) Diphtheria toxin
C) Tetanus toxin
D) LPS of Salmonella
Which of the following traits is characteristic of an exotoxin?
A) Poorly immunogenic
B) Pyrogenic
C) Species specific mode of action
D) Low toxicity
Which exotoxin binds to the presynaptic terminal membrane at the neuromuscular junction,
blocking the release of acetylcholine?
A) Diphtheria toxin
B) Tetanus toxin
C) Botulinum toxin
D) Cholera toxin
The toxin of Vibrio cholerae is classified as an
A) exotoxin.
B) endotoxin.
C) enterotoxin.
D) exerotoxin.
What is the enzyme found in saliva that cleaves glycosidic linkages in the peptidoglycan of the
bacterial cell wall?
A) Lactoperoxidase
B) Lactoferrin
C) Hyaluronidase
D) Lysozyme
Which is a major virulence factor that prevents phagocytosis by the host defense systems?
A) Capsule
B) Exotoxin
C) Pili
D) Streptokinase
The body site(s) affected by the activity of enterotoxins is/are the
A) motor neurons.
B) brain.
C) small intestine.
D) upper respiratory tract.
A human being vaccinated against the influenza virus will experience a(n) __________ rather
than a(n) __________ if he/she comes into contact with the influenza virus at a later time.
VERO/FALSO

In practice, sterility is difficult to achieve.

Heat is probably the most widespread method for controlling microbial growth.

In general, vegetative cells are more heat resistant than bacterial endospores.

Filter sterilization is used primarily to eliminate viruses from the filtrate.

Bacteriostatic agents inhibit bacterial growth but do not specifically kill the organisms
against which they are directed.

Cell wall synthesis can be inhibited by bacteriolytic agents.

Semisynthetic penicillins are generally more broad-spectrum than are nonsemisynthetic penicillins.

The tetracyclines are protein synthesis inhibitors.

Antimicrobial activity is measured by determining the smallest amount of agent needed
to inhibit the growth of a test organism, a value called the __________.

When a host is infected with a microbe, disease does not necessarily follow.

Infection and disease are synonymous terms.

Because of its very low pH (about pH 2), the stomach is virtually sterile.

Pathogenic strains of Corynebacterium diphtheriae are converted to nonpathogenic
strains when the pathogenic strains are invaded by β phage.

Iron is a critical trace element which can influence the growth of a pathogen in a host.

Fragment B of the diphtheria toxin binds to the host cell receptor.

Fragment A of the diphtheria toxin interferes with protein synthesis.

Fever is a universal symptom of the action of an exotoxin.

One milligram of pure botulinum toxin is sufficient to kill more than one million guinea
pigs.

A few microorganisms are pathogenic solely because of the toxins they produce. (In
other words, invasion of the tissue is not required for pathogenicity)

The enterotoxins of Escherichia and Salmonella have modes of action similar to that of
the cholera toxin.

The polysaccharide capsule of Streptococcus pneumoniae prevents phagocytosis by
the host's immune system.